"The agency began its canine program in 1975 to detect explosives. It uses Belgian Malinois because they are small and have short hair -- making it easy for them to work in the heat. They are also very sociable.

"Each dog and its handler has to complete 20 weeks of training before beginning work, the agency said.

"When it's time for a dog to retire -- usually after about 10 years -- it is retired to its handler."